This blog is a lab notebook for my work with the Reprap open source 3D printing undertaking.

Tuesday, November 16, 2010

Taking a different direction

A few months ago, I had planned on acquiring another BfB Rapman with two print heads this time so that I could explore the use of PLA as a support material for ABS prints.

With the sale of BfB to 3D Systems, continuing troubles with BfB firmware and the catastrophic failure of my expensive Rapman hot end and the discovery that BfB isn't warranting such failures, I've decided to build my own second printer.

8 comments:

I may be missing something. How does buying a Lathe help you with making a printer?

Only the hot end requires a lathe at all, and only some hot end designs at that. Most designs require only a drill press at most. Many can be made reliably with only a hand drill.

I found a little trick that allowed me to perfectly drill out brass round stock, haven't tried bolts yet.

Clamp the drill bit to the workbench, mount the stock in the drill. Spin up the drill and touch them together. If it shakes, try again until it's perfectly steady. Then press inward, letting the resistance of the piece inform what angle you hold the drill at. If it's not perfectly aligned it tries to align, so let it.

I thought that was common knowledge, as I found the directions on the wiki. Or in the forum or something. It's been awhile.

That's possible. Forrest's focus seems to have been on accessible designs - things that are easy to replicate. Requiring a lathe seems to be against that philosophy.

And if all you wanted was *a* hot end, seems cheaper to buy it.

Of course, it's always nice to have more tooling. I'm going to get a lathe myself eventually.

He mentioned it in the context of his broken hot end, implying that until he gets it he can't print, which seems a little off. So I though I'd ask if there where perhaps some ulterior motives involved here.

It's really no big mystery. I have a number of projects, 3D printing being only one, that will benefit from having a lathe.

I am presently running a BfB Rapman 3.0 and have had many hours experience with it. I know it's strengths and weaknesses and suspect that I can improve on things in a kaizen manner in building a follow-on printer.

My epiphany with BfB printing came when I realised that I was spending more money on hot ends than I was on the filament that goes through it. That is simply unacceptable.

I had a couple of spare BfB hot ends in stock and was able to get back to printing after I replaced the extruder top plate with an aluminum equivalent.

I've stopped buying hot ends from BfB and ordered two new ones from Laszlo Krekacs in Hungary. Laszlo does a variation on nophead's power resistor hot end design. If Laszlo's prices stay low enough, I will buy from him. If not, I'll design my own, not that I am excited about doing that.

The lathe for me is aimed at the filament pump of the extruder. I have a notion that I could design a dual hot end extruder that used a single stepper motor if I was clever enough. I want to see if I can do that.

I also have with the lathe the capability to cut my own lead screws and nuts for the z-axis of my next printer. Those are not an inconsiderable expense and are much better than the threaded studding that Rapman, Mendel and Darwin use.

Forrest - A site that will help you with your lathe is http://www.littlemachineshop.comThey have all the replacement parts for all of the small lathes and such.Also be for warned that the next purchase will be a mini-mill. It just happens when you find out what you can do with metal. Please note that if it gets out of hand you will know when you build a foundry out of a 5 gallon bucket and melt metal.Other than that good luck and have fun.